I have fx-9860g slim and the procedure is very simple
?->N:?->M ;input rows and columns
{N,M}->Dim Mat A ;this creates matrix N×M
"A"?->A ; input matrix element
A->Mat A[1,1] ;assign matrix element A to position 1,1 of matrix A
But this doesn't work for Classpad.
How can I set the matrix dimension and how to assign a matrix element to desired position in Classpad?